This invention relates to an automatic mechanical brake adjuster and more particularly to the employment of a tooth and pawl or ratchet mechanism which provides increment adjustments together with an adjustable link which controls the back-off distance for the brake shoe. Heretofore various mechanical brake adjusting mechanisms have been suggested. In U.S. Pat. No. 3,195,689, for instance, an adjustable link maintains a relatively uniform back-off distance for brake shoes. The use of ratchet-action slack adjusters is shown in U.S. Pat. Nos. 4,161,240; 1,989,207 and 3,895,538. The present invention is an improvement over the brake mechanism shown in U.S. Pat. No. 3,659,681 which does not employ an automatic slack adjusting mechanism.